Rollup merge of rust-lang#59170 - varkor:const-generics-rustdoc, r=QuietMisdreavus,eddyb

Add const generics to rustdoc

Split out from rust-lang#53645. This work is a collaborative effort with @yodaldevoid.

The `FIXME`s are waiting on a refactor to `LazyConst`. I'll address these in a follow up, but I thought it would be better to implement the rest now to avoid bitrot.

r? @QuietMisdreavus

Author: Mark-Simulacrum

src/librustc/hir/print.rs

@@ -591,12 +591,12 @@ impl<'a> State<'a> {
                 self.s.word(";")?;
                 self.end()?; // end the outer cbox
             }
-            hir::ItemKind::Fn(ref decl, header, ref typarams, body) => {
+            hir::ItemKind::Fn(ref decl, header, ref param_names, body) => {
                 self.head("")?;
                 self.print_fn(decl,
                               header,
                               Some(item.ident.name),
-                              typarams,
+                              param_names,
                               &item.vis,
                               &[],
                               Some(body))?;

src/librustdoc/clean/auto_trait.rs

@@ -435,7 +435,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                     let new_ty = match &poly_trait.trait_ {
                         &Type::ResolvedPath {
                             ref path,
-                            ref typarams,
+                            ref param_names,
                             ref did,
                             ref is_generic,
                         } => {
@@ -444,7 +444,13 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                                                                 .expect("segments were empty");
 
                             let (old_input, old_output) = match last_segment.args {
-                                GenericArgs::AngleBracketed { types, .. } => (types, None),
+                                GenericArgs::AngleBracketed { args, .. } => {
+                                    let types = args.iter().filter_map(|arg| match arg {
+                                        GenericArg::Type(ty) => Some(ty.clone()),
+                                        _ => None,
+                                    }).collect();
+                                    (types, None)
+                                }
                                 GenericArgs::Parenthesized { inputs, output, .. } => {
                                     (inputs, output)
                                 }
@@ -469,7 +475,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
 
                             Type::ResolvedPath {
                                 path: new_path,
-                                typarams: typarams.clone(),
+                                param_names: param_names.clone(),
                                 did: did.clone(),
                                 is_generic: *is_generic,
                             }
@@ -669,7 +675,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                             match **trait_ {
                                 Type::ResolvedPath {
                                     path: ref trait_path,
-                                    ref typarams,
+                                    ref param_names,
                                     ref did,
                                     ref is_generic,
                                 } => {
@@ -724,7 +730,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                                         PolyTrait {
                                             trait_: Type::ResolvedPath {
                                                 path: new_trait_path,
-                                                typarams: typarams.clone(),
+                                                param_names: param_names.clone(),
                                                 did: did.clone(),
                                                 is_generic: *is_generic,
                                             },